Geological Bulletin Univ. Peshawar Vol. 35, pp. 125-137,2002

IFTIKHAR AHMED ABBASI', M. ASIF KHAN^, MOHAMMAD ISHFA' & P.K. ~00~4 'Department of Geology, University of Peshawar 'NCE in Geology, University of Peshawar 3LandmarkResources, 41CIMOD,Katmandu, Nepal.

ABSTRACT: The area around town is inherently vulnerable to mass movement p rocesses, most commonly due to landsliding. It is characterized by high degree of erosivity and erodibility due to both natural and man inducedfactors. The area ispart of ayoung orogenic belt that is experiencing one of the world's most rapid upliff rates, and is located in the near vicinity of major thrustfaults. Shear zones associated with still activefaults, such as Murree Thrust and also thefoldinggenerated due to thrustinginduce an inherited weakness and natural instability in the rocks of the area. This compounded with ever increasingpopulation pressure, deforestation, large-scale construction work in theform of residential and commercial buildings and road network havefurther aggravated the problem. Lithologically the area is comprised of shale, siltstone and sandstone belonging to the Oligocene-Miocene Murree and Kuldana formations. In order to study the landslides and other mass movement problems in Mun-ee, an area around the main town and alongtheMuwee-Kashmir Highway is selectedfor detailed analysis of theproblem. The eastern slopes of the Murree ridge, and the road section between Jhika Gali and Aliot village are worst affected by the landsliding. Around Murree town, major landslidessuch as Shijang Hotel, Midway and MIT landslides, located on the upslopes of the Jhika Gali-Lawrence College Bypass road are caused by inadequate drainagesystemfrom the city centre (Murree ridge). In mostpart of the area around Murree ridge, creep is a common phenomenon in thick colluvium coverdue to obvious loss of vegetation. The area between Jhika Gali and Aliot village is aZso afected by landsliding, and some of the largest landslides such as Aliot, Birgran and Kasseri landslides have inflictedgreat damage tofarm andforest land. This area is located in thefootwall of the MBTand is deformed byfolding and termination splays associated with it. Mast of the landslides initiated at the colluvium-bedrock interface, but once initiated the tension cracks spread into the bedrock and therefore causing thefailure in it. Major landslides in the area exhibita complex array ofjointflracture pattern both parallel and perpendicular to the bedding, and in various ways contribute to the mass movement. d

INTRODUCTION collision of the Indian plate with the Eurasian plate during Eocene time along a suture zone known as The town ofMurree in Himalayan foothills lies the Main Mantle Thrust (MMT) (Tahi&heli et al,, about 50 km to the northeast of Islamabad, the 1979; Coward et ale, 1986), and is one of the ~pitalof (Fig. I), at an elevation of approxi- world's most rapidly uplifting region on earth (Zeitler, mately 2200m. The Himalaya was created by the 1985). The deformation progressively migrated

Geological control on natural hazards: earthquakes and mass movement. Khan, M.A., Abbasi, LA., & Khattak, G.A. (Eds.). Geological Bulletin, University of Peshawar, (Special Issue), Vol. 35, pp. 125-137, 2002 Geological Bulletin Univ. Peshawar Vol. 35, py. 125-137,2002 126

southward away from the Early Eocene collision nism of failure in the landslide prone parts of the zone at the MMT and reached the Himalayan foot- area, The study was conducted with the help of Survey hills by Miocene time. The Himalayan foothills, ofPakistan topogaphic maps, interpretationof digital commonly known as the sub-Himalayas (Gansser, SPOT panchromatic image, and extensive fieldwork. 1964) are defined as a set ofrocks which are bounded by major thrust faults such as Main Boundary STRUCTURAL GEOLOGY Thrust (MBT) and the Main Frontal Thrust (MFT) Structurally the area around Murree is com- to the north and south respectively (Fig. 1). The plexly deformed by MBT and folding associated with Murree area lies in a seismically active zone due it (Fig. 2) (Chambers, 1992; Iqbal and Bannert, to its proximity with the active Murree Thrust 1998). The Murree Thrust trending NE-SW, is an (local name for MBT) along which magnitude 4.5 to emergent fault passing close to Bansra Gali, Chitta 5.0 earthquakes on the Richter scale have been Mor, Sunny Bank and Kuldana (Fig. 2). Most part of recorded as recently as 1977. Nevertheless, earth- the central ridge on which the Murree Town is quakes of magnitude 6 and more can be expected located is a SW plunging syncline with the Murree along this zone. Formation lying in the core ofthe syncline, and the The molasse sediments (siltstone and sand- beds dipping inwards towards the core ofthe ridge. stone) of the Murree and Kuldana formations (Oli- This structure provides a degree ofstructural stabil- gocene-Miocene) constitute most part ofthe Murree ity to the ridge. At the same time, combined with a Hills. The sandstone of the Murree Formation is red lithological setup of alternating sandstone-siltstone- to reddish gray in colour, multistoried, fine to claystone layers, this structure makes the Murree medium grained, cross-bedded, hard and compact ridge a major reservoir ofwater. This is evident from constitutes 4-6m thick sequences that occasionally the presence ofmany springs and seepages at the toes attain thickness of over 10m. The sandstone se- of major sandstone horizons (Rafiq et al., 1989). quences are interbedded with red colour, 10's of This seepage often facilitates slippage ofthe rock and meters thick siltstone and shale. These fine-grained soil bodies at slopes and thus contributes to mass facies constitute most part of the formation and movement. provide a week zone for most of the faults to pro- The topographichigh ofthe Pindi Point is in the pagate through it, Landsliding and other mass move- core of a major anticline in which over 2km thick ment phenomenon are inherited to the area due to section of the Murree Formation molasse is exposed. weak component lithologies, complicated and in- The bedding youngs towards north and dips range tense deformation compounded in recent times by from 20-60" to almost vertical across the fold axis. anthropogenicfactors like deforestation, construction Near Bansra Gali steeply dipping strata becomes and over-population etc (Neiderer and Schafber, 1989). older, transitionally passing from the Kuldana For- This paper describes landslide prone areas mation into the Chor Gali Formation (late Eocene around the Murree town, especiallyalong major road age), characterized by platy, nodular, nummulitic sections, i.e., Bansra Gali-pika Gali-LawrenceCol- limestone and interbedded greenish marls. In this lege ring road, Jhika Gali-Aliot, and the Jhika Gali- area the Murree Thrust is SE verging and brings the road sections along the Kashmir Highway Chore Gali Formation over the Murree Formation (Fig. 2). 1t describes some selectedlandslides from indicating a mainSE transport direction along the the area with special emphasis on the geological Murree Thrust. Kashmir point lies tothe southeast processes that contributed in the initiation of the of the axis of the major syncline with NW dipping mass movement processes. Detailed geotechnical (50-60") outcrops. The area between Kashmir Point analyses were conducted tounderstand the mecha- and Jhika Gali appears to have been folded by a series Geological Bulletin Univ. Peshawar Vol. 35, py. 125-137,2002

A / Main KarakuramThrust

Gilgit e

Kohistan Island Arc

100 km

Major Thrust Faults River Features T -*--- + Federal Boundary N Fig. 1. Generalized map of N. Pakistan with study area around Murree as inset. Geological Bulletin Univ. Peshawar Val. 35, pp. 125-137,2002

Kls Als Mls CIS Shls Mwls Ksls Dls Sb MR. AR Bg Kd Bb Gc Cm + -E J-

Fig. 2. Detailed location and landslide distribution map of Murree town and surrounding area. Most of important landslides especially those along the Bansragali-Jikagali-Lawrence College ring road, and JikagaIi-Bhurban, JikagaliAliot road sections are marked. Main Boundary Thrust (MBT) is oriented NE-SW direction. Localized faults are marked as broken lines.

of isoclinal folds. A large number of inter-molasse planes) behind the slope face is a determining factor faults may be present in this area but are difficult to for slope instability. In most of the studied area, recognize in the field. The shear zones associated particularly in major landslide areas such as Kashmiri with still active Murree Thrust and also the folding Bazar and ChittaMor landslides a detailed survey of generated due to thrusting induce an inherited weak- the joint orientation was carried out, ness and natural instability potential in the strata of the Murree hills. These are potentially weakzones in LANDSLIDE PROCESSES AND a slope and their strength is less than the surround- MECHANISM ing intact rock. Presence of smallshear zones in shale In order to understand the processes and mecha- beds further reduces its strength that is crucial for its nism involved in the landslide activity in the area, stability. Deformation due to faulting and orienta- two major landslides are selected for detailed stud- tion of rock discontinuities (joints and bedding ies, one at Chitta Mor and other at Kashmiri Bazar Geological Bulletin Univ. Peshawar Vol. 35, pp. 125- 137,2002

(Fig. 2). These slides are mapped at 1:500 on Field observations topographic maps prepared with the help of theodo- The landslide is typically a translational type lites and plane tabling. with a complex nature of displacement (Figs. 3). The KASHMIRI BAZAR LANDSLIDE escarpment of the slide is clear on the hillside face and is irregular in shape (Fig. 3). The maximum width This landslide is located about 5 km NE of of the unstable area measures to be about 100 meters Murree, on the Murree-Kashmir road (Fig. 2). Locally along the road section, but is substantially reduced this road connects Murree with the prime hotel to about 20m in the downslope ofthe road (Fig. 3). resort at Bhurban, and ultimately to Kashmir valley The total length ofthe landslide is about 350m) 35m reflecting its strategic and tourist importance. A on the hillside and rest below the road. The direction topographic base map at a scale of 1:500 has been of movement of the slide is at right angle to road prepared for this purpose, which has also been used alignment that runs in the direction ofNE. The main for detailed geotechnical analysis (Fig. 3). body of the slide is lying below the road but has been The landslide occurred in a section ofthe road leveled by extensive engineering work. between Garial Camp and the Kashmiri Bazar (Fig. 2). The main escarpment towards the hillside is The slide involves the rocks of the Murree Forrna- composed ofbedrock in which the major movement tion, including siltstone, shale and sandstone. These took place (Fig. 3). Within the bedrock, anumber of lithologies are prone to mass-movement upon exces- new weak horizons are developing, such as just sive saturation. The general trend of outcrops in the below the main escarpment towards the northern slide area is N120W/400NE, almost at right-angle to margin of the slide. These surfaces are future's thelocal slope. Sandstone beds are exposed in parts potential sliding surface. Similar weak horizons or of the escarpment, particularly in its SE part above tension cracks are developing in the colluvium cover the road. Thin, 1-2m thick sandstone beds are just above the crown of the slide. These cracks are exposed in the upper part or crown of the escarpment up to lOcm wide and fairly unstable. Downslope the (Fig. 3). About one metre thick sandstone bed lies in road, the movement is probably located at the the lower part of the escarpment that is underlain by interface between the colluvium and the bedrock. a sequence of alternating siltstone and shale. The The bedrock is also exposed on the sides of the slide. sandstone beds are laterally inconsistent and their thickness changes even on the outcrop scale. The The slope above and below the road section is sandstone is fine to medium grained, thin to medium distinctly different. The slope above the road varies bedded, hard and fractured. Most part of the slide from 30-35", whereas the slope below the road is only area (above the road), however, is comprised ofshale about 20". The slope above the landslide on the and siltstone. There is a thin layer of colluvium in this hillside gradually flattens to a minimum towards the area. A number of sandstone ridges are partially ridge top. The forest cover is fairly thick above and exposed upslope of the landslide. The upslope of the on sides of the landslide. The colluvium cover is landslide is moderate to high, whereas, the about 4 meters thick upslope of the landslide but downslope is generally moderate. The upslope area thins out to only about 2m around the landslide. The is covered with fairly thick pine forest. A number of colluvium cover has been more or less completely local streams (nullahs) from the upslope military removed from the landslide escarpment. The bed- camp used to drain through the landslide zone. New rock is generally at shallow depth. On the hillside, channels have now been constructed arbund the the depth of the bedrock is estimated to be about landslide to direct the water from these nullahs into 2 metres, while on the valley side it could be 4-6 the channels. metre deep. Geological Bulletin Univ. Peshawar Val. 35, pp. 125-137,2002 130

Map of Kashmiri Bazar Landslide

Tension Cracks Escarpment Retaining Wal Outcrops

Scale

Fig. 3. Kashmiri Bazar landslide map. The landslide is mapped on 1500 scale in order to show tension cracks developed along the scarp of the landslide. The landslide body is removed through civil work and a network of channels is constructed to stabilize it. Geological Bulletin Univ. Peshawar Vol. 35, pp. 125-137,2002 13 1

The landslide is generally dry for most part of ENE, with a great majority in the direction of NE. the year, but during monsoon rain bursts a number The sense of slip indicated by these linear structures of small streams (nullahs) start flowing through the varies from dip-slip to a combined strike-slip unstable area. Nullahs on both sides of the landslide and dip-slip component. In addition to this drain water from the upslope and also from the predominant set of joints, two sets with a rela- settlement on top of the ridge into the major stream tively moderate density of distribution are downslope. There is an extensive network of noticed. One ofthese sets comprises joints oriented channels built to drain this water away from the NW-SE and dipping steeply to the NE or SE with unstable zone. most being almost vertical. Third of the sets is least frequent and is oriented NS with steep dips to Geotechnical analysis (joint and the west. fracture data) It is clear from the Fig. 4 that the most predomi- The escarpment of the Kashmiri Bazar slide nant set of jointslfractures is oriented parallel exposes a number of outcrops ofthe bedrock. Several to or at angles less than 30" to the escarpment of the sets ofjoints and fractures are noticed in the bedrock slide. Furthermore, the NE direction of slip particularly in the sandstone. Figure 4, shows that and a normal to strike-slip sense of movement poles to the jointlfracture planes are distributed is in parallelism with the mass-movement direc- mainly in the NE, SE, and SW quadrants of the tion of the landslide. This compatibility between equal-area net. Within this general distribution the kinematic attributes of the landslide and there is a greater concentration of the poles in the those of the jointslfractures in the bedrock SE quadrant suggesting preponderance of joints1 suggest that the latter are genetically related with fractures oriented NE-SW and dipping moderately the landslide phenomenon and not to the to steeply towards NW i.e., the facing direction regional tectonics. We interpret that the predomi- of the slide. In most cases the surfaces of these nant set of joints in the bedrock in the landslide joints are marked with striations and slickensides. area, particularly those exposed in the escarpment These striationslslickensides are marked with a area, are tension jointslfractures induced by the direction of movement ranging from NNW to slope-instability. The gravity sliding of the blocks

Joint 1 *I

Fig. 4. Jointlfracture plot of Kashmiri Bazar landslide. a) Pole plot showing NNE slip direction,b) Joint and fracture planes with slickensides. Geological Bulletin Univ. Peshawar Vol. 35, pp. 125-137,2002 132

down-dip or oblique to dip-direction resulted vulnerable to inass movement. The Chitta Mor in the development of striations/slickensides at the landslide being described here is part ofthis active jointlfracture surfaces of the intact blocks. The unstable zone. observed genetic relation between the joints and the The instability of the area can be attributed to landslide has important bearings on the mechanism complex geology. The Murree Thrust (MBT)out- ofthe landslide. crops in the near vicinity of the landslide, bringing the Slide mechanism Chore Gali Formation of the Eocene age over the rocks of the Kuldana and Murree formations (Oli- - The road through Kashmiri Bazar is an old link gocene-Miocene age). The unstable zone also lies at between Kashmir and other parts of the country. the contact of the Kuldana Formation with that of Since past many years it also became significant due the Murree Formation, in the core of a major syn- to its touristic importance as it connects a number cline. Severe tectonic activity in the area has led to oftourist resorts and scenic countryside. Due to ever the development of a network ofjoints and fractures. increasing visitors each year, the road was widened by excavating the hillside. The current site of the The landslide is mapped at 1:500 scale topo- Kashmiri Bazar landslide has been unstable since graphic map, with contours at 1 metre interval long and the mass movement activity has been (Fig. 5). The activity map of the landslide was common. Roadexcavation work hrther compounded prepared by demarcating stable and unstable zones, the problem and the road now runs in a U-shape. tension cracks, landslide escarpment and bedrock The road cut appears to be the triggering mechan- outcrops. ism, which then continued due to the rain and Field observations sewerage water on the surface and weathering of insitu soft rocks. There is a great probability that the The landslide has taken place in colluvium, also initial slip occurred along the colluvium-bedrock involving some bedrock belonging to the rocks ofthe interface due to excavation at the toe of the slope Murree Formation. Colluvium is thick and supports during the widening of the road. Much of the thick vegetation (pine trees) around the landslide later landslide activity, however, involved formation area. Creep is common in unstable colluvium. The of tension cracks that penetrated through the bedrock involved in the mass movement includes colluvium as well as the underlying bedrock as shale and siltstone with interbeds of sandstone joints and fractures. Much of the landslide body (Fig. 5). About 2m thicksandstone body is located is thus a mixture of colluvium, shale, silt and in the centre of the escarpment, and is laterally sandstone blocks slipped along favourably oriented inconsistent in thickness. Sandstone is the most set of joints. resistant lithology, but it is only about a metre thick towards the Murree end of the slide. The sandstone CHITTA MOR LANDSLIDE is fine to medium grained, greyish brown to brown The landslide occurs on the -Murree in colour, multistoried, thin to medium bedded, Highway and is located between Chitta Mor and highly fractured and jointed. Major part of the Bansra Gali (Fig. 2)) about 6km short ofMurree. It landslide, both on the hillside as well as on the valley has a longhistory ofinstability and has been disrupt- side is comprisedofshale and siltstone, however, on ing the road since 1965 (Khan et al., 1987). As shown the valley side, major part of the slide zone is now in Fig 2, much of the 2 km strip of the Murree- occupied by the dumped material. Islamabad road between Chitta Mor and Bansara Gali The unstable zone is about 120 m wide, while is classified as an unstable zone, and therefore the major landslide with clear escarpment is 80m Geological Bulletin Univ. Peshawar Vol. 35, yy. 125-137, 2002 133

Chitta Mor Landslide

Legend

Tension Crocks Main escarpment Unstoble Zones N Stable Zones E2.I Retaining Wall Scale Outcrops

O- meters 10

Fig. 5. Detailed map of Chitta Mor landslide at 1:500 scale. The landslide (Cls on Fig. 2) is located halfway between Bansragali and Chitta Mor. The landslide has been stabilized through engineering work but new tension cracks are developing close to the escarpment. wide. The road is oriented in SEE-NWdirection, The movement direction along the main land- which alsois direction of the escarpment (Fig. 5). On slide is towards N200E at right angle to the road Bansra Gali end ofthe escarpment, another potential orientation. The escarpment is very steep to vertical unstable zone is also threatening the road, and is but flattens to only about 20"-25" above the escarp- therefore included in the active landslide, The land- ment. On the valley side the downslope is also about slide is about 150m long, about 20m on the hillside 20". There is a thick forest cover on the sides of the (up to the escarpment) and the rest on the valley side. landslide, particularly on the hillside. There is a On the valley side most of the landslide material has perennial stream flowing on the Murree end of the been leveled for the engineering remedial work by the slide. On the valley side, the stream banks are Highway Department. unstable and are sliding into stream bed. The High- Geological Bulletin Univ. Peshawar Vol. 35, pp. 125-137, 2002 134

way Department has constructed a network of chan- set of joints is oriented ENE-WSW with moderate nels in order to regulate the rainwater away from the dips to the NNW. The escarpment of the slide is unstable zones, however, these drains are now defined by this set of joints. These joints are com- broken and disrupted due to unstable nature ofthe monly associated with the slickensides and stria- colluvium. tions similar to those observed and described from the Kashmiri Bazar slide (see above). In all the cases, The colluvium cover is over 2m thick close to the hanging block has been noticed to have slided the landslide upslope of the road. Large tension down-dip or oblique to dip within the general direc- cracks are developing in the colluvium cover and a tion ofthe mass-movement. The second set ofjoints number of unstable zones can be recognized (Fig. 5). is oriented NNW-SSE with steep dips to the NE. This The colluvium cover can therefore be divided into set ofjoints is at high angle to the first joint set and stable and unstable zones. These unstable zones may the plane of the slide, but has a general parallelism become potential landslides during next rainy sea- with the slip direction in the landslide. It is therefore sons. One such large unstable zone is located on the envisaged that this joint set has important contribu- Bansra Gali side of the landslide (Fig. 5). It has a well- tion to the mass movement in the landslide area. A developed scarp which is gradually increasing, later- third set of minor joints is noticed parallel to the ally joining with the escarpment of the major land- bedding plane. These joints together with the bed- slide. The colluvium within the zone is highly frac- ding plane are oriented at high angle to slip plane as tured with a series of tension cracks indicating well as the slip direction and are thus non-contribu- movement within the body. A small rain water tory to the mass movement in the Chitta Mor channel constructed through the colluvium has been landslide. badly disrupted and broken at a number of places. The zone is oriented NNW, at right angle to the road Slide mechanism and is threatening the retainingwall. The Chitta Mor landslide on the eastern slope A similar unstable zone occurs upslope of the of the Murree ridge is a major landslide which main escarpment with a fairly regular outline (Fig. 5). initiated during early 70s. The landslide is part of a The colluviurn in the zone shows strong creep and major unstable zone close to main Islamabad-Murree even movement as reflected by abundant tension road section. This zone is about one km long, which cracks. This zone is highly unstable and will ulti- hosts a number of large and small landslides, most mately join the main escarpment. On the valley side, of which are under different phases ofstabilization. just below the road, another zone of unstable collu- This area is deformed structurally by a major thrust vium occurs towards the Murree end. fault in the area, known as the Murree Thrust (also called the Main Boundary Thrust). The fault brings Geotechnical analysis carbonate rocks of the Eocene age on top of the (fracture and joint data): Miocene molasse sediments. Complex sets ofjoints The outcrops, particularly the sandstone beds in the slide area are associated are highly fractured and jointed. We have collected DISCUSSIONS AND orientation data for the joints in the sandstone outcrops exposed in the escarpment area. Figure 6, RECOMMENDATIONS shows an equal area projection of measured joint The instability in the Murree area is partly due planes, bedding and poles to the both. The poles to to its inherited geological characteristics and cli- the joint planes have a three-fold distribution sug- matic conditions, and partly due to human factors. gesting presence of three sets ofjoints. The principal It is difficult to overcome the natural causes but it is Geological Bulletin Univ. Peshawar Vol. 35, pp. 125-137, 2002

Poles to Joints Slide Plane @ID@ Poles to Bedding Bedding - Striations/Slickensides Joint Plane 1

Fig. 6. Jointlfracture plot of Chitta Mor Landslide. The NNW oriented joint plane (joint set 3) that is locally sub- parallel to the escarpment is the principal slip plane. Lineations plunge moderately to the NNE are in the general slip direction of the landslide.

greatly needed to reduce the effects of human activi- walls and most of the channels constructed for ties contributing to landslide problem. The area diversion of drainage water have been broken. New around Murree is extremelyfragile but little work has scarps are developing along major tension cracks on

-----been done sofa50 evaluate the risks of erosion and the hillside and movement has started along them. ------mass movement. Major emphasis has so far been on ~imila~y~a~e-Sc5eTn@nZZg~~fa~ctro~a~ the engineering base remedies, which have been bilize the MIT landslide, and major part of the partially successful but have limited scope. Major engineering structure is already in disintegration engineering work at the Chitta Mor landslide has during the first monsoon rains. Engineering methods stabilized the movement for the time being but the addedwith bioengineering techniques is considered enormous load added due to large scale concrete effective to control soil erosion and mass movement, work on thevalley side has started showing adverse such as in the Kashmiri Bazar landslide area. Same effects. Large cracks are developing in the retaining techniques should be adopted at other landslide Geological Bulletin Univ. Peshawar Vol. 35, pp. 125-137,2002 136

prone areas along with an efficientsurface drainage One ofthe crucial observation of this study is and sewerage system. reactivation of apparently stabilised old land- slide zones. Excavation in these zones and A number of major landslides such as the MIT and Shifang Hotel landslides on the Murree Bypass unmanaged drainage causes these zones to road section appear to be direct result of the poor commonly reactivate and trigger major new drainage system from the Forthview Hotel and Shifang landslide mass-movement. Hotel respectively into the slide areas. Major con- Studyo fa selected few major landslides dern- struction work in the Murree Improvement Trust onstrates that the landslides in the Murree area Housing scheme is major strain on the eastern slope are primarily triggered by the slope failure along of the Murree ridge. The construction work is being the bedrock-colluvium interface mainly in re- carried out without much regard to natural drainage, sponse to excavation for road construction/ resulting in excessive undercutting by the water widening. Once initiated, the escarpment pro- during monsoon rains. gressively migrates upslopes engulfing steep There is also an urgent need to prepare compre- tension cracks. At this stage the landslides hensive landuse and hazard maps not only for the involve both the colluvium as well as the bed- Murree Town but also for the adjoining areas. This rock. Joint planes, both pre-existing as well requires detailed study of the area over a longer as those related with the slope failure facili- period of time. No attention has been paid to most tate rock sliding leaving behind striations/ of the landslides located away from the main roads slickensides on planar surfaces of the intact or highways. Largearea is erodedalong major steams bedrock. in the area where people are forced to abandon their Acknowledgements: This study wasfinanced by the houses and valuable land due to landslides. Most of International Centrefor Integrated Mountain Devel- these landslides are not even marked on a proper opment (ICIMOD), Nepal. Mr. Pardhan Pramod of map. MENRIS at ICIMOD motivated and encouraged con- SUMMARY ducting this work. Mr. Tariq Mahmood Satti, Chief Coordinator,Murree--KotliSattian Develop- The slopes encircling the Murree ridge, which ment (MKKD) Islamabad provided valuable hosts the old ~urreetownship are generally information and literature relating to erosionalprob- unstable despite a reasonably thick forest cover. lerns of the area. Shamsul Hadi helped in field an This is mainly due to unmanaged sewerage computer work. outlet and excavation work for road and build- ing construction. REFERENCES The ring road encircling the Murree ridge is Abbasi, I. A. 1994. Clay minerals in the Himalayan generally unstable. In particular the Jhika Gali- Foreland-basin sediments indicating an uplifting Lawrence College Bypass road section is the orogenic belt. In: Geology in South Asia, Proceed- unstable zone designated in this study, This is ings of the 1st. GEOSAS conference (Riaz Ahmed mainly due to a relatively steeper slope on this and Arshad M. Sheikh edits.), 280-284. side of the Murree ridge, as well as a relatively Chambers, A. F. 1992. Kinematics of the frontal Hima- thin vegetation cover, sewerage disposal from layan thrust belt, Pakistan and the external west- the old Murree township on this sideandlarge- ern Alps, France. Unpubl. Ph.D, dissertation, scale new construction work, particularly in the Imperial College London. 369p. area downslope the bypass road in the form of Coward, M.P.,Windley, B.F., Broughton, R.D., Luff,

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